Nurses in England and Wales were forced Thursday to cancel part of an upcoming strike after a High Court judge ruled it would be unlawful.
Royal College of Nursing (RCN) general secretary Pat Cullen said the union would no longer stage the walkout next Tuesday.
But the union leader said they would press ahead with planned industrial action starting late Sunday and continuing Monday.
The stoppage, originally intended to last for 48 hours but now curtailed to around 28 hours, is the latest by the RCN as a dispute over pay and working conditions intensifies.
Members earlier this month voted to reject a five-percent government pay offer to end their months-long industrial action, one of many across the UK public and private sector following a year of double-digit inflation.
Union bosses, who had backed the pay deal, then announced an escalation of its walkouts to include staff in emergency departments, intensive and cancer care units for the first time.
In Thursday's ruling in London, judge Thomas Linden concluded that the six-month period allowed for strike action from the moment the union votes on it, expires at midnight on Monday.
The UK government applied to the High Court for the injunction, insisting it was acting on a request from NHS Employers, which represents state-run hospital groups in England and Wales.
Welcoming the decision, Health Secretary Steve Barclay said he supported the right to walk out "within the law", but that the government "could not stand by and let plainly unlawful strike action go ahead".
"We took this step with regret to protect nurses by ensuring they are not asked to take part in an unlawful strike," he added.
Barclay also urged them to agree exemptions in key healthcare areas for the days when the stoppage will still go ahead.